Motion picture apparatus



Oct. 4, 1932. F. L. BROWN 1,880,406

MOTION PICTURE APPARATUS Filed Nov. 28. 1928 INVENTOR firzzmwzzifivm BYZ2 ATTdRNEY Patented Oct. 4, 1932 UNITED STATES PATENT OFFICE FREEMANLEE BROWN, 01 WILMERDING, PENNSYLVANIA, ASSIGNOR T WESTING- HOUSEELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYL- VAN IAMOTION PICTURE APPARATUS Application filed November 2a, 1928. Serial No.322,368.

My invention relates to motion pictureapparatus, and it has particularrelation to apparatus for the simultaneous reproduction of pictures andsounds from film-records thereof. Q

During the process of making a photographic sound-record on alight-sensitive film and during the process of reproducing the soundtherefrom, it is necessary that the moving film shall be prevented fromvibrating in the slightest degree. .It is also highly important that thefilm shall travel at an absolutely uniform speed past the point at whichthe record is made, or is reproduced, since even the most minorspeedvariations cause unpleasant changes in the pitch of the reproducedsounds.

The two requirements, constant film speed and freedom from vibration,are diflicult to meet if the film is drawn through a film gate of theusual type by a constant-speed sprocket during the recording orreproducing processes, since the spring-pressed filmshoes exert abraking action on the film that causes a vibratory phenomenon, commonlyknown as chattering, very similar to that which occurs when a dampenedfinger is rubbed over a pane of glass.

It is, accordingly, an object of my invention to provide a film-gateparticularly adapted to guide a film past the point at which sounds areto be photographically re corded thereon.

Another object of my apparatus is to provide a film-gate adapted for usein talkingmotion-picture apparatus.

Another object of my apparatus is to provide a film-gate wherein a film,during its passage therethrough, is prevented from transverse vibrationand is not subjected to forces tending to cause longitudinal vibration.

Another object of my invention is to provide a film-gate wherein thefilm is forced to assume such a curvature that a. line of light fallingupon it at the recording or reproducing point lies in an element of acylinder, the axis of which is transverse to the motion of the film.

Another, and more specific, object of my provide an improvedfilmstructing a film-gate in the form of two-relatively movable curvedplates, the curvature of the plates being such that the light from therecording or reproducing lamp impinges upon the film where its curvatureis most pronounced. By reason of the greater rigidty given to the movingfilm through curving it at the recording and reproducing point, I amenabled to greatly reduce the spring tension with which the film-shoesare pressed agamst'it, thus lessening the tendency toward chattering ofthe film as it is drawn through the gate.

In addition, I have provided an improved film-shoe of a semi-floatingtype, which has suflicient resiliency to permit the passage thereunderofa splice and, at the same time, exerts just the rightiamount ofpressure upon the moving film.

The novel features that I consider characteristic of my invention areset forth with particularity in the appended claims: The inventionitself, however, both as to its organization and its method ofoperation, together with additional objects and advantages thereof, willbest be understood from the following description of a specificembodiment, when read in connection with the accompanying drawing, inwhich:

Figure 1 is a perspective view of a film-gate comprising a preferredembodiment of my invention, a film-guide-assembly being omittedtherefrom for the sake of clarity.

Fig. 2 is a top view of the film-gate.

Fig. 3 is a perspective view of a film-shoe together with itsaccompanying tensionspring, and

Fig. 4 is a perspective view of the filmguide-assembly disassociatedfrom the filmgate.

The apparatus illustrated in Figs. 1 and 2, constituting a preferredembodiment of my invention, comprises a front-gate-member 1 consistingof a front plate 2, having an aperture 3 therethrough, and alongitudinally curved front wear-plate 4. afiixed thereto by a pluralityof screws 5.

The front wear-plate is provided with a plurality of longitudinallyextending, oppositely disposed, raised tracks 6 and 7, on which tracksthe edges of a film are adapted to ride in order that the central partof the film, including that portion of the emulsion thereon devoted tothe pictures as well as the sound record, shall not come in contact withthe plate.

The sound record, whether it is of the constant-density, variable-areatype, or of the variable-density, constant-area type, is usuallydisposed longitudinally of the film, closely adjacent to the sprocketholes and, for that reason, the front wear-plate is provided with alight-opening 8 intermediate the tracks 6 and 7 and close to the'track7. In order that the light-opening 8 shall be definitely located withrespect to the aperture 3 in the frontplate 2, the wear-plate isprovided with a plurality of dowel-pins 10 that extend through openingsin the front-plate with minimum clearance.

It is highly important that the moving filir shall be prevented fromside-slip during both the recording and reproducing processes and, toobviate the chances of slip, a plurality of edge-guiding discs 11 and12, of the type shown in Fig. 4, are so mounted between pivots 13 and 14carried by a plurality of upstanding ears 15 and 16 on the front platethat they make contact with the edges of the film in its passage throughthe gate.

The discs 11 and 12 are rotatably supported on a shaft 17, the disc 12,which is disposed adjacent to the edge of the wear-plate closest to thelight-opening, being prevented from moving toward the pivot 14 by acollar 18 affixed to the said shaft. The discs are further provided withhub-portions 20 and 21 that extend toward, andmake contact with, eachother intermediate of the discs, thus defining the minimum spacingtherebetween. Inequalities in the width of a film are accommodated bypermitting the disc 11 to move slightly axially of the shaft 17 againstthe pressure exerted by a small spring 22.

In order that a longitudinally-travelling film shall be prevented frommovement axially of the openings through the front gatemember, means areprovided for holding the edges of the film against the tracks 6 and 7 inits travel thereover. As shown in Figures 1 and 2, the holding means Iprefer to employ comprises a plurality of frictionshoes of the typespecifically illustrated in Fig. 3. Each friction-shoe comprises twoU-shaped presser-feet 23, that are inter-connected through a fiat,resilient member 24 lying in a plane parallel to the plane defined bythe wearing surfaces of the feet.

The friction-shoes are loosely mounted at the upper and lower ends,respectively, of a rear plate 25, the resilient members 24 of the shoeslying rearwardly of the plate and the presser-feet extending throughopenings in the plate toward the raised tracks 6 and 7.

In the drawing, I have shown the rear plate 25 as having a curvaturesimilar to that of thefront wear-plate. Such curvature, however, is notnecessary, it being sufficient that the friction shoes shall be sosupported, in any convenient manner, that their wearing surfaces lietangential to a curved surface parallel to the surface defined by thesaid tracks.

In order that the presser-feet shall be resiliently urged towards thetracks, a spring 26, having bent-down end portions 27, as shown indetail in Fig 3, is provided for each friction shoe. Each spring 26 isheld firmly against the rear face of the rear plate 25 by a centrallydisposed mounting screw 28, the upper one only of the said screws beingvisible in the drawing.

Each bent-down end portion of each of the springs 26 engages the innersurface of one of the presser feet constituting the friction shoe withwhich the spring is associated, the said presser-feet, accordingly,being individually and independently urged toward the film. By reason ofthe inter-connecting member 24, however, any movement of one of thepresser feet is transmitted, in part, to its companion foot, thuspermitting the friction shoe, as a Whole, to more easily overrideinequalities in the film caused by splices and the like.

The rear plate is affixed to a rear platecarrying member 30, the saidplate and member being hereinafter designated the rear gate-member Therear plate-carrying memher, which has a large opening centrally thereofin alignment with an opening 31 extending through the rear plate, isprovided with a plurality of diametrically disposed bosses 32. Each bossis provided with a passage-way through which extends a guide-pin 33 thatprojects laterally from a rear supporting-device 34, the bosses and thecorresponding guide-pins constituting means whereby the rear gate-membermay be slidably supported with respect to the front-gate member 1.

A pin 35, having a circular notch near the free end thereof, projectsfrom the rear supporting device, and extends through an opening in theplate-carrying member 30 to cooperate with a gravity-actuated hasp 36.The pin and hasp constitute means by which the rear gate-member may beheld in the open position, as illustrated in Fig. 1, against thepressure of a plurality of springs 37, each of which encircles one ofthe guide pins 33.

A finger piece 38 may be aflixed to the rear plate-carrying member 25 bya screw 40, as illustrated, for conveniently manipulating the gate,although this is not absolutely es sential.

- The rear supporting-device 34 should be rigidly connected to the frontgate-member, it being preferable, for this purpose, to provide the saidsupporting device with a plurality of integral extensions 41 and 42 thatare dove-tailed to the edge of the front-plate.

The rear-plate 25 should be provided with means for limiting the extentof its movement toward the front wear-plate 4, a plurality of small pins43 projecting from the face of the rear-plate being satisfactory forthis purpose. Only one of the pins is visible in Figure 1, the oppositepin being hidden behind the front-plate.

The rear supporting-device 34 is provided with a large central opening44, in alignment with the openings through the front and reargate-members, in which a photo-sensitive device may be disposed when myimproved film-gate is utilized in a sound-reproducing machine. Acylindrical element 45 is preferably positioned in the opening 44 toshield the photo-sensitive device from light other than light fallingthereon after having been modified by its passage through asound-record.

I have not illustrated my improved filmgate as being afiixed to anyparticular part of a moving picture machine, a film-phonograph, orequivalent apparatus, inasmuch as the manner in which it is incorporatedinto such devices is immaterial.

From a careful consideration of the foregoing description, the operationof my improved film-gate should be substantially self evident to thoseskilled in the art. When it is desired to thread a film through thedevice, the finger piece 36 may be grasped to move the rear gate-membertoward the rear supporting device. As the gate-member moves rearwardly,the pin 35 enters the opening in the gate-member provided therefor, andthe pointed end thereof, engaging the hole in the gravity-latch 36,lifts the latterto such position that it is permitted to thereafter fallinto the circular notch on the pin. To close the gate, it is onlynecessary to lift the end of the gravity-latch, permitting the edge ofthe opening therein to clear the notch in the pin, whereupon the springs37 urge the rear gatemember forward until movement thereof is stopped bythe limit-pins 43.

A film, in its travel over the front-plate is so curved that, at thelocation of the lightopening, a transverse element thereof is positionedin an imaginary cylindrical surface, the axis of which is parallel tothe upper and lower edges of the said opening. The film therefore,cannot bend longitudinally, or wobble, immediately adjacent to the lightopening, thus entirely eliminating one source of distortion thathitherto has been extremely troublesome.

Since the film, by reason of the curvature it is caused to assume intraveling through the gate, is largely prevented from bendinglongitudinally, and from wobbling, the resser-feet need only exert avery slight amount of pressure in order to hold the film between themand the tracks, and no pressure need be exerted on the film opposite tothe light-opening. The reduction of pressure on the film substantiallyeliminates the chattering phenomenon hereinbefore referred to as asource of distortion, and is an important phase of my invention.

Although I have chosen a film-gate of a specific form for purposes ofillustration, my invention is not to be limited thereto, but it is to berestricted solely by the limitations imposed thereon by the prior artand by the spirit of the appended claims.

I claim as my invention.

1. In apparatus for use in connection with a photographic film, a frontgate-member having a face provided with tracks at the opposite sidesthereof adapted to support a film, the central portions of said trackshaving the surfaces of congruent sections of a cylinder and the endportions of said tracks having the surfaces of planes tangent to thesections of the cylinders at their extremities and coextensive withthem, and means for resiliently urging a film against said tracks, saidmeans coacting with said film along said end portions.

2. In apparatus for use in connection with a photographic film, a frontgate-member having a face, the central portion of which has the surfaceof a cylinder and the end portions of which have the surfaces of planestangent to and coextensive with said cylindrical surface at itsextremities, a rear gatemember having a plurality of shoes to engagesaid front gate member on said end portions, and means for resilientlyurging said rear gate-member toward said front gate-member.

3. In film-handling apparatus, an aperture-plate, a shoe-carrying plate,means for slidably supporting said shoe-carrying-plate, spring means forurging said shoe-carryingplate toward said aperture-plate, means forguiding said shoe-carrying-plate in its motion relative to saidaperture-plate, means for limiting the distance between saidshoe-carrying-plate and said aperture-plate to a predetermined value,means for locking said shoecarrying-plate in a position away from saidaperture-plate, means for laterally guiding the film in its passage oversaid apertureplate, and means for resiliently clamping said film againstsaid aperture-plate.

In testimony whereof, I have hereunto subscribed my name this 23rd dayof November,

FREEMAN LEE BROWN.

